I don't think human production is linear. There's definitely an optimal point, and it probably varies from person to person. I think, actually, past that point your productivity declines rapidly.

I would not be surprised at all if working 70 hours a week yields more productivity than 80, which yields more than 100.

And productivity can even become negative, i.e. if you're overworked/tired you might end up creating more work to fix the mess you made later.

That’s because you actually work 6 days a week.

Yeah but what's the argument?

Perhaps you should split the load with another human?

That's out of my control.